Activated macrophages, present in excess during natural inflammatory responses, bear the potential to kill and eradicate cancer cells. Macrophage activation has been demonstrated to require the serum-borne vitamin D binding protein (known as Gc protein), as well as B and T lymphocytes. However, in various cancer patients the Gc protein is deglycosylated by serum α-N-acetyl galactosaminidase (Nagalase) secreted from cancer cells. This deglycosylated Gc protein, lacking the N-acetylgalactosamine monosaccharide, cannot be converted to its form of Macrophage Activating Factor, leading to immunosuppression rather than Macrophage activation against cancer cells.